Matter is generally classified into two groups namely: the pure substance and mixtures. Pure substances include elements and compounds. An element is made up of only one kind of atom while compound is made up of two or more elements combined chemically in definite proportions. Elements may be metals, non-metals, metalloids and inert gases.
Mixtures are either homogeneous or heterogeneous. Homogeneous mixture is one in which only one phase is present while heterogeneous mixture is one in which the components can be distinguished from another.
A. Pure Substances
Place the glass tube flat on the table and measure the desired length. Make a single scratch with 2 strokes of the triangular file. Do not saw. Grasp the tube firmly with both hands, with the thumb opposite the scratch and break the tubing with one snap by pushing with both thumbs away from you.
1. Note down the color, state and solubility of the following:
- Iron Fillings
- Carbon Tetrachloride
- Sulfur Powder
- Copper Wire
- Copper Sulfate
- Sodium Chloride
- Mossy Zinc
2. On separate watch glasses, place a pinch of Iron Filling and Sulfur Powder. Compare the effect of a bar magnet on the 2 substances.
3. Place Iron filling in a test tube and a pinch of Sulfur. Heat for about 2 minutes. Compare the result from the original iron filling and sulfur powder. What king of substance is sulfur? Iron? After heating the mixture, was there a new substance formed.
Prepare the following mixtures by grinding the components in a mortar and pestle:
- Pinch of salt and 20 ml of water
- Corn starch and flour
- Sand and iron fillings
- Sugar and sand
Note: Whether they are homogeneous or heterogeneous mixtures; derived a method in separating each of the above mixtures.